export default {
  bind(el, binding, vnode, oldVnode) {
    let resizeEvent = new CustomEvent('drag-resize', { detail: '尺寸变化', bubbles: false });
    // 初始化不最大化
    el.fullscreen = false;
    // 当前宽高
    let nowWidth = 400;
    let nowHight = 300;
    // 当前顶部高度
    let nowMarginTop = 0;
    // 获取弹框头部（这部分可双击全屏）
    const dialogHeaderEl = el.querySelector('.el-dialog__header');
    let hasSetBodyHight = false;
    // 弹窗
    const dragDom = el.querySelector('.el-dialog');
    dragDom.className += ' el-drag-dialog';
    // 清除选择头部文字效果
    dialogHeaderEl.onselectstart = new Function("return false");
    // 头部加上可拖动 cursor
    dialogHeaderEl.style.cursor = 'move';

    // 获取原有属性
    const sty = dragDom.currentStyle || window.getComputedStyle(dragDom, null);

    // 头部插入最大化最小化元素
    let maxMin = document.createElement("button");
    maxMin.className += ' el-dialog__headerbtn el-dialog__minmax';
    maxMin.style.right = '40px';
    maxMin.style.color = '#909399';
    maxMin.title = el.fullscreen ? '还原' : '最大化';
    maxMin.innerHTML = '<i class=' + (el.fullscreen ? '"el-icon-crop"' : '"el-icon-full-screen"') + ' onMouseOver="this.style.color=\'#409EFF\'" onMouseOut="this.style.color=\'inherit\'"></i>';
    dialogHeaderEl.insertBefore(maxMin, dialogHeaderEl.childNodes[1]);

    let moveDown = (e) => {
      const disX = e.clientX - dialogHeaderEl.offsetLeft;
      const disY = e.clientY - dialogHeaderEl.offsetTop;

      let styL, styT;

      if (sty.left.includes('%')) {
        styL = +document.body.clientWidth * (+sty.left.replace(/\%/g, '') / 100);
        styT = +document.body.clientHeight * (+sty.top.replace(/\%/g, '') / 100);
      } else {
        styL = +sty.left.replace(/\px/g, '');
        styT = +sty.top.replace(/\px/g, '');
      }

      document.onmousemove = function (e) {
        const l = e.clientX - disX;
        const t = e.clientY - disY;
        dragDom.style.left = `${l + styL}px`;
        dragDom.style.top = `${t + styT}px`;
      };

      document.onmouseup = function (e) {
        document.onmousemove = null;
        document.onmouseup = null;
      };
    };
    dialogHeaderEl.onmousedown = moveDown;
    let bodyHeight = 'auto';

    function setMaxMin() {
      if (el.fullscreen) {
        let i = maxMin.querySelector('.el-icon-crop');
        i.classList.remove('el-icon-crop');
        i.classList.add('el-icon-full-screen');
        maxMin.innerHTML = '<i class="el-icon-full-screen"></i>';
        maxMin.title = '最大化';
        dragDom.style.height = "auto";
        dragDom.style.width = nowWidth + 'px';
        dragDom.style.marginTop = nowMarginTop;
        el.fullscreen = false;
        dialogHeaderEl.style.cursor = 'move';
        dialogHeaderEl.onmousedown = moveDown;
        dragDom.querySelector('.el-dialog__body').style.height = bodyHeight;
        hasSetBodyHight = false;
      } else {
        let i = maxMin.querySelector('.el-icon-full-screen');
        i.classList.remove('el-icon-full-screen');
        i.classList.add('el-icon-crop');
        maxMin.title = '还原';
        bodyHeight = dragDom.querySelector('.el-dialog__body').offsetHeight + 'px';
        nowHight = dragDom.clientHeight;
        nowWidth = dragDom.clientWidth;
        nowMarginTop = dragDom.style.marginTop;
        dragDom.style.left = 0;
        dragDom.style.top = 0;
        dragDom.style.height = "100VH";
        dragDom.style.width = "100VW";
        dragDom.style.marginTop = 0;
        el.fullscreen = true;
        dialogHeaderEl.style.cursor = 'initial';
        dialogHeaderEl.onmousedown = null;
        if (!hasSetBodyHight) {
          let footerHeight = dragDom.querySelector('.el-dialog__footer') && dragDom.querySelector('.el-dialog__footer').offsetHeight;
          dragDom.querySelector('.el-dialog__body').style.height = 'calc(100% - ' + (dialogHeaderEl.offsetHeight + footerHeight) + 'px)';
          hasSetBodyHight = true;
        }
      }
      // 确保事件冒泡
      const resizeEvent = new CustomEvent('drag-resize', { detail: '尺寸变化', bubbles: true });
      el.dispatchEvent(resizeEvent);
    }

    maxMin.onclick = setMaxMin;
    dialogHeaderEl.ondblclick = setMaxMin;
  },
};